in proportions, the following percentages being-
Copper . . . ... ... ° 3
Tin ... ......... -. 84 9°
Antimony ... .. ... 8 7
of white metal for bearings is that it can be
run the the journal is in place, and so ensure a-
fit. It causes considerably less friction than brass or
To sum up then, alloys of copper and tin are termed bronzes,
and a little zinc added up to about i \ or 3 per cent.
of and 2inc are called brasses, Muntz metal being
one of ; and those having tin and antimony, with a little
^ Brazing.Brass or gun metal may be united by this process,
is also termed hard soldering; and the joint will then
be as as the original casting.
or steel may be also connected by brazing if more
especially finished pieces of work. The method is to
first clean the work with acid, then take some brass
mix with powdered borax as a flux, the borax being
moistened with water.* The filings are placed between
the to be braced so as to form a joint, as much surface
for the latter as possible, and the two are held together
in tongs, having thick jaws to keep the heat. The tongs
will the and grip the pieces until perfectly set,- and the
be finished off in the vice.
If the work cannot be easily gripped, another way is to insert
the as before, and, binding with iron wire, place the' pieces '
in a coke fire until the operation is complete.
Or, still another method is to use the blow-pipe. Here a fine
of very hot is directed on to the work by blowing with'
this instrument through a lighted 'Bunsen.' *
* ge&omfy^ Instead of brass Slings, 'spelter* is used, which' is a
about equal parts of copper and zinc, and specially'
ft* bntafug pturposes* . ... :- '